An alkaline protease from Kocuria kristinae F7: properties and characterization of its hydrolysates from soy protein

作者：Feng, Zhen^*; Chen, Xi; Li, Juan-juan; Ren, Dan

来源：European Food Research and Technology, 2013, 236(2): 293-301.

DOI：10.1007/s00217-012-1890-9

• Alkaline proteases
• Kocuria kristinae
• Enzymatic properties
• Hydrolysates
• Soy protein

An alkaline serine protease (SF1) from Kocuria kristinae F7 was purified. The molecular mass of the SF1 protease was estimated to be 57 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The N-terminal amino acid sequence of the first 14 amino acids of the SF1 protease showed low homology with bacterial proteases, suggesting that the enzyme had not been described previously. The SF1 protease exhibited maximal activity at pH 9.0 and 60 A degrees C. The activity of the SF1 protease was enhanced by the presence of Ca2+ and Mg2+ ions. It showed high stability in the presence of NaCl and ethanol. Reverse-phase high-performance liquid chromatography (RP-HPLC) analyses indicated that soybean protein isolates treated with the SF1 protease generated four principal new hydrophilic peptides. Mass spectrometry analyses indicate that the distribution of molecular weight of these peptides was from 0.705 to 1.305 kDa. Hydrolysis of soybean protein isolates with the SF1 protease increased the level of total free amino acids, essential amino acids and flavor amino acids. The SF1 protease may decrease the bitterness of soy protein hydrolysates. The results showed that the SF1 protease of Kocuria kristinae F7 appears to be good candidate enzyme for potential application in acceleration of fermented soybean food ripening.

• 出版日期2013-2
• 单位东北农业大学